The present invention relates generally to electronic streak camera structures, and more particularly to an electronic streak camera structure having no moving parts for accurate imaging of high speed transient events.
Conventional streak camera systems for measuring temperature of energetic environments have been substantially dominated by system noise, the primary effect of which is that energy gathered for in each measured wavelength is somewhat higher or lower than true readings. In a conventional streak camera, a mirror is rotated in the pupil of the optical system to separate time events onto a fixed focal plane. A prism or diffraction grating is typically used to disperse the optical energy onto a detector. Mechanical jitter of the rotating mirror inherently introduces error into the measurements. Additionally, conventional streak cameras are light-inefficient and are typically ten stops lower than a standard electronic camera, reducing the amount of light collected by a factor of 100 or more. To amplify the light, photomultiplier tubes or multi-channel plates are used, which introduce substantial additional noise. Only general radiative characteristics can be obtained with these systems because of the limited signal-to-noise performance.
The invention solves or substantially reduces in critical importance problems with conventional streak camera structures by providing a streak camera including a spectrometer having no moving parts for use in recording high speed transient events. The camera of the invention is characterized by low noise and low cost of operation, provides improved light efficiency (two orders of magnitude) and greater light collecting capability (f/2 vs f/20) compared to conventional streak camera structures, and permits temperature determinations accurately for highly dynamic test events such as internal combustion in engines, materials deformation in hot metal processing and detonating or deflagrating explosives, including measurements at very high rates of temperature change (hundreds of degrees per millisecond).
For the purpose of describing the invention and defining the scope thereof, the term "optical" shall, in accord with customary usage, be defined herein to include only ultraviolet, visible, near infrared, mid-infrared and far infrared regions of the electromagnetic spectrum lying between about 0.1 to about 1000 microns (see, e.g., Optical Physics, Max Garbuny, Academic Press, NY, 1965, pp 1-6), and more specifically to the range of from about 0.2 micron, the approximate lower limit of operation of fine quality quartz lenses (Garbuny, p 280), to about 50 microns, the approximate upper limit of operation of long wavelength transmitting material such as thallium bromide-iodide ionic crystal (Garbuny, p 282).
It is therefore a principal object of the invention to provide an electronic streak camera.
It is another object of the invention to provide an electronic streak camera for use in high-speed pyrometry of energetic materials.
It is a further object of the invention to provide an electronic streak camera having no moving parts.
It is a further object of the invention to provide an electronic streak camera for acquiring temperature data on explosive materials.
It is yet another object of the invention to provide an electronic streak camera for acquiring temperature data at high rates of temperature change.
These and other objects of the invention will become apparent as a detailed description of representative embodiments proceeds.